The present invention relates to a dispensing device provided with a filter member and, more particularly, to a device for separating fibrin and particulate material from blood serum and for dispensing small amounts of the filtered serum.
U.S. Pat. No. 3,322,114, issued to Portnoy et al. May 30, 1967, discloses an apparatus for securing a sample of blood plasma which includes a hypodermic needle for drawing a blood sample directly from a human or animal and a small container for receiving the sample. The apparatus of Portnoy et al. also serves as a dispenser and may include a filter member to separate the serum from the fibrin and other particulate matter. While admirably suited for its intended purpose, the apparatus of Portnoy et al. is less suited for use in applications where it is desirable to run a number of tests from a given blood sample. For obvious reasons it is undesirable to inject a needle into a blood donor merely for the purpose of collecting a separate test sample. To use the apparatus of Portnoy et al. as a filter and dispenser for a previously collected blood sample, it would be necessary to remove the dispensing nozzle and filter member assembly from the mouth of the container, place a blood sample within the container, and then replace the dispensing nozzle and filter assembly. The handling of the dispensing nozzle which would be necessitated by such a procedure would endanger the cleanliness and sterility of the nozzle and filter assembly.
U.S. Pat. No. 3,449,081, issued to Hughes June 10, 1969, discloses a container/dispenser for deparating particulate matter from blood serum by filtration and for dispensing the serum in dropwise fashion. The filter member of the assembly disclosed by Hughes is carried in the cap and is adfixed to the container after the blood sample is placed therein. However, the blood filtrate or serum is dispensed directly through the cap which must first be removed and then replaced after the container has received the blood sample. No provision is made for protecting the cap dispenser from contamination during handling.